In general, the procedure for assembling an insulating window structure involves placing one sheet of a glazed structure, such as glass, over another in a fixed, spaced relationship, with a spacing and sealing means located at and along the periphery of the two structures, thereby forming a sandwich-type structure having a sealed air space between the structures. The sealed air space provides improved insulation capabilities. Difficulties exist, however, in the manufacture of the windows, especially the deployment and positioning of the sealant spacer strip.
To keep the glazed structures properly spaced apart, a rigid spacer strip is formed into a frame and placed between the two structures to maintain proper spacing after which the sealant composition is injected into a channel formed by this spacer frame and the edges of the glazed structures. Alternatively, the rigid spacer can be pre-coated with sealant and placed into the space between the glazed structures to form the insulating window structure.
Sealant spacer strips can be continuous whereby a single strip runs without interruption along the entire periphery of the glass sheet and has the flexibility to be bent into corners. When using flexible spacers, the degree of flexibility should be sufficient to permit a spacer to be bent around a corner. If it is not flexible enough, the spacer must be cut or notched to facilitate this bending. The manual application of a continuous strip, however, can require considerable ability on the part of the installer, especially to form consistent corners and if corners require notching, to properly place the notch. Also, continuous spacer strips may need to be removed and re-positioned, if the spacer strip is placed in incorrectly on the glass sheet.
One conventional method of assembling or making an insulating window unit consists of starting at one corner applying an adhesive strip, typically a sealant spacer strip, along a peripheral edge of a glazed structure, forming corners where required, cutting the strip to length after formation of the last corner and then positioning a second glazed structure thereon to form a panel with an sealant spacer strip holding the glazed structures apart from each other.
Applying the sealant spacer strip by hand can be time consuming and result in poor or inconsistent positioning of the sealant spacer strip. Also, the manufacturer must apply pressure by hand to get the sealant spacer strip to adhere to the glass sheet. The inconsistency of this pressure results in inconsistent adherence of the sealant spacer strip to the glass sheet.
In order to alleviate some of these problems, application tools have been used to lay down sealant spacer strips on glass sheets. These tools require that the sealant spacer strip be threaded through the tool and must remain threaded in the tool until a complete assembly is fabricated. Many application tools make it difficult to reposition a mis-deployed threaded strip, because the device cannot be easily disengaged from the sealant spacer strip and re-deployed in the middle of fabricating an insulating glass unit. Instead the tool must be run back over the strip to the place of mis-deployment and then the strip re-positioned. This is often not possible forcing the window manufacturer to scrap the mis-deployed strip. Also, many of the tools do not provide capabilities for determining where the sealant spacer strip should be notched for cornering.